I hope you're open for some constructive feedback, cos i can see that a lot of work has gone into this.
- I feel like you need juicier movement - think of acceleration and inertia - and shooting. The muzzle flash of that base gun is confusing, the projectile is irritatingly slow, lacks punch. sound is one major reason for that. is it intentional that i have a lot of guns on number keys from the start?
- the level structure is an interesting touch, but map layouts have dead ends that make you (slowly) backtrack tediously. left-over enemies are not pointed out, i have no idea what to do and where to go at times.
but all that stuff can be fixed. keep it up, appreciate how you're going for something of your own here and kudos for what you achieved up to here.